A Near-Infrared Spectrometer Based on Novel Grating Light Modulators

Wei Wei,Jie Zhang,Weimin Chen,Ning Wang,Zhu Jin,Shanglian Huang

doi:10.3390/s90403109

Abstract

A near-infrared spectrometer based on novel MOEMS grating light modulators is proposed. The spectrum detection method that combines a grating light modulator array with a single near-infrared detector has been applied. Firstly, optics theory has been used to analyze the essential principles of the proposed spectroscopic sensor. Secondly, the grating light modulators have been designed and fabricated by micro-machining technology. Finally, the principles of this spectroscopic sensor have been validated and its key parameters have been tested by experiments. The result shows that the spectral resolution is better than 10 nm, the wavelength deviation is less than 1 nm, the deviation of the intensity of peak wavelength is no more than 0.5%, the driving voltage of grating light modulators array device is below 25 V and the response frequency of it is about 5 kHz. With low cost, satisfactory precision, portability and other advantages, the spectrometer should find potential applications in food safety and quality monitoring, pharmaceutical identification and agriculture product quality classification.

Highlights

Near-infrared spectroscopy [1,2,3] is widely used for chemical analysis, food safety and quality monitoring, materials inspection and the monitoring of dynamic process, etc
The programmable grating used in digital transform spectrometer proposed by Polychromix, Inc. has a Micro-opto-electromechanical systems (MOEMS) grating designed with multi-layer structure to solve this problem
A near-infrared spectrometer based on a novel grating light modulator is proposed in this paper

Summary

Introduction

Near-infrared spectroscopy [1,2,3] is widely used for chemical analysis, food safety and quality monitoring, materials inspection and the monitoring of dynamic process, etc. (2) Nondispersive methods, including arrays or sequences of fixed filters, or Fourier Transform spectroscopy (FTIR) Each of these techniques provides different combinations of resolution, speed, sensitivity and cost. A near-infrared spectrometer based on this technology with many advantages such as cost effectiveness, portability, low power consumption, high speed, and miniaturization has become one of the most interesting research topics in the near-infrared spectroscopy field. This kind of handheld spectroscopic sensor with a competitive price can be used for a range of applications that have been restricted to larger and more expensive instruments up to now.

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